How to Measure Fetal Growth 2017
Women's Health Care Physicians
8 Nov New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study. Ultrasound Obstet Gynecol ; Taipale P, Hiilesmaa V. Predicting delivery date by ultrasound and last menstrual period in early gestation. Obstet Gynecol Ultrasound measurement of the embryo or fetus in the first trimester (up to and including 13 6/7 weeks of gestation) is the most accurate method to establish or confirm gestational age. . New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study. addressed as dating policies and the identification of growth related problems should be used to assess fetal size and should not normally be used to . New charts for ultrasound dating of pregnancy. Ultrasound Obstet Gynecol ; – 3. National Collaborating Centre for Women's and Children's. Health.
By continuing to browse this site you agree to us using cookies as described in About Cookies. Wiley Online Library is migrating to a new platform powered by Atypon, click leading provider of scholarly publishing platforms. For more information, please visit our migration page: Previous article in issue: Frontomaxillary facial angle in trisomy 21 fetuses at 16—24 weeks of gestation.
Next article in issue: Specific weight formula for fetuses with abdominal wall defects. Correct assessment of gestational age and fetal growth is essential for optimal obstetric management. The objectives of this study were, first, to develop charts for ultrasound dating of pregnancy based on crown—rump length and biparietal diameter and, second, to derive reference curves for normal fetal growth based on biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference and femur length from 10 weeks of gestational age onwards.
A total of pregnant women click here included for analysis in this population-based prospective cohort study. All women had repeated ultrasound assessments to examine fetal growth.
Charts for ultrasound dating of pregnancy, based on crown—rump length and biparietal diameter, were derived.
Internal validation with the actual date of source showed that ultrasound imaging provided reliable gestational age estimates. The earlier the ultrasound assessment the more accurate the prediction of date of delivery. After 24 weeks of gestation a reliable last menstrual period provided better estimates of gestational age.
Reference curves for normal fetal growth from 10 weeks of gestational age onwards were derived.
In current clinical medicine, data coming from medical records and analysis are often used to document diagnostic issue, giving the opportunity of a systematic data meta-analysis to improve patient care and to develop new health-assessment techniques. These differences are likely to arise from different statistical methods and the way in which pregnancy was dated. After 24 weeks of gestation a reliable last menstrual period provided better estimates of gestational age. No part of this publication may be reproduced, stored in a retrieval system, posted on the Internet, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Ultrasound examination provided a better estimate of the date of delivery than a reliable LMP before 20 weeks of gestation.
Charts for ultrasound dating of pregnancy and reference curves for fetal biometry are presented. The results indicate that, up to 24 weeks of pregnancy, dating by ultrasound examination provides a better prediction of the date of delivery than does last menstrual period.
The earlier the ultrasound assessment in pregnancy, preferably between 10 New Charts For Ultrasound Dating Of Pregnancy And Assessment Of Fetal Growth 12 weeks, the better the estimate of gestational age. Reliable information on gestational age is important for assessment of fetal size and fetal growth. Early detection of fetal growth restriction or macrosomia may help to reduce associated morbidity and mortality 12. Accurate information on gestational age is also important to avoid unnecessary obstetric interventions at the time of delivery 3.
Gestational age is historically derived on the basis of the first day of the last menstrual period LMP 4. It has been established that embryos follow the same growth pattern in early pregnancy 6. Therefore, more accurate information on gestational age can be provided by ultrasound assessment and this is widely recognized to be the method of choice 78. Controversy remains about the measurement of choice and the optimal gestational age for assessment Numerous studies have been conducted to derive reference charts for fetal size.
Many, however, had a suboptimal design, using a hospital-based population or having an inappropriate sample size. Additionally, substantial differences in reference charts exist depending on the population and the method of pregnancy dating 12 Reference charts are often based on measurements taken from 12 or more weeks of gestation onwards 1214 Nowadays high-resolution ultrasound imaging makes assessment of fetal biometry possible at an even earlier stage of pregnancy, so reference charts from earlier pregnancy onwards could have additional value.
Finally, growth charts might need an update, owing to the availability of improved ultrasound equipment with higher resolution and changing health status.
There is a clear need for lucent dating methods and new growth charts derived from a large population-based cohort study, using serial measurements The first aim of this population-based study was to develop charts for ultrasound dating of pregnancy based on CRL and BPD. The second aim was to construct new reference charts for fetal growth parameters, including BPD, head circumference HCtransverse cerebellar diameter TCDabdominal circumference AC and femur length FLfrom 10 weeks of gestation onwards.
The Generation R study is a population-based, prospective cohort study from early fetal life until young adulthood. The study has been designed to identify early environmental and genetic determinants of growth, development and health All pregnant women in a previously defined area in Rotterdam, the Netherlands, were continue reading either by a community midwife or hospital-based Generation R staff at their first antenatal visit.
They received written and oral information about the study. Women who gave written consent and had a viable pregnancy at the first ultrasound visit were included. In total, pregnant women with a delivery date between April and January were enrolled in the prenatal part of the study.
During the prenatal period, data were collected longitudinally from questionnaires, physical examinations and fetal ultrasound assessments. Gestational age was established by ultrasound imaging during the first visit. The individual time scheme of these assessments depended on the specific gestational age at enrollment as described previously The study design is described in detail elsewhere Flow chart of participants in the Generation R study. Further restrictions were applied when deriving charts for ultrasound dating of pregnancy.
Methods for Estimating the Due Date - ACOG
For this analysis, data from pregnant women were available for derivation of charts for ultrasound dating of pregnancy Figure 1. The first day of the LMP was obtained from the referring letter from the community midwife or hospital. The date was confirmed with the pregnant woman at the first ultrasound visit, and additional information on regularity and duration of the cycle was collected.
CRL was measured in early pregnancy if feasible. Standard ultrasound planes for fetal measurements were used as described previously 1019— Briefly CRL was measured in a true mid-sagittal plane with the genital tubercle and the fetal spine longitudinally in view. The maximum length from cranium to the caudal rump was measured as a straight line. BPD and HC were measured in a transverse section of the head with a central midline echo, interrupted in the anterior third by the cavity of the septum pellucidum with the anterior and posterior horns of the lateral ventricles in view.
For BPD the outer—outer diameter was measured perpendicular to the midline and for HC an ellipse was drawn around the outline of the skull.
For the TCD click here the transducer was rotated from the transverse plane for measurement of the BPD towards the cerebellum in the back of the head while keeping the cavity of the septum pellucidum in view. The optimal plane was reached when the peduncles were visualized with a symmetrical shaped cerebellum. The calipers were placed on the outer, lateral edges of the cerebellum.
AC was measured in a symmetrical, transverse, round section through the abdomen, with visualization of the vertebrae on a lateral position New Charts For Ultrasound Dating Of Pregnancy And Assessment Of Fetal Growth alignment with the ribs. The measurement was taken in a plane with the stomach and the bifurcation see more the umbilical and hepatic veins using an ellipse around the abdomen.
Difference between Gestational age and Fetal age - gestational age VS fetal age
FL was measured with the full length of the bone in view perpendicular to the ultrasound beam. Transvaginal scanning was performed in case of limited visibility by transabdominal scanning in early pregnancy. The remaining examinations were carried out in one of five hospitals in the vicinity under guidance of Generation R staff. All sonographers were experienced and underwent additional training according to guidelines from The Fetal Medicine Foundation to achieve optimal reproducibility.
Quality checks were carried out frequently to assess the correctness of the ultrasound sections used for biometry measurements and placements of the calipers. Feedback was provided when needed to optimize individual performance. As experience in early pregnancy is limited, intraobserver and interobserver reproducibility of fetal ultrasound measurements from read more to 14 weeks of gestation was assessed in 21 pregnancies.
The ICC was higher than 0. Thus we could reliably construct reference curves for fetal size from early pregnancy onwards for clinical purposes. Pregnancy outcome and information about labor and birth were obtained from the midwife or physician who attended the delivery. The information was collected on a specially constructed Generation R report form. For all participants, it was known whether the pregnancy resulted in live birth, miscarriage, perinatal loss, neonatal death or elective termination.
Data were analyzed as recommended by Altman, Chitty and Royston 13 Even though strict inclusion criteria were applied by selecting participants with a reliable LMP, there were still outliers with a LMP that seemed unlikely 5.
We used previously published relationships to identify the unlikely data points.
Verhulst more info, Henning TiemeierTonya WhiteAssociations of maternal folic acid supplementation and folate concentrations during pregnancy with foetal and child head growth: An additional advantage is that some major structural defects can be detected by ultrasound examination in early pregnancy after 10 weeks of gestation In total, pregnant women with a delivery date between April and January were enrolled in the prenatal part of the study. In order to evaluate the applicability of these standards to current patients, we compared data accumulated in our research data system to determine whether our patients were categorized appropriately. Figure S2 Individual values for fetal head circumference in millimeters plotted on the appropriate reference range median and 3rd, 10th, 90th and 97th centiles with gestational age.
Data points more than two SDs from the regression line, fitted on our data, were considered to be unrealistic and were therefore removed. For derivation of charts for ultrasound dating, gestational age was log-transformed to stabilize variance 13 The best fitting curve was determined using second-degree fractional polynomials The curve was fitted using repeated measurement analyses, taking into account the dependency in the data by specifying a constant covariance between measurements of the same subject.
Subsequently, in pregnancies in which both CRL and BPD were measured, the mean and the SD of estimated gestational age were compared to derive the optimal cut-off point for ultrasound dating of pregnancy.
Internal New Charts For Ultrasound Dating Of Pregnancy And Assessment Of Fetal Growth was carried out, comparing the actual date of delivery with the estimated date of delivery based on both ultrasound examination and LMP, to establish whether pregnancy dating by ultrasound imaging is indeed superior to the use of LMP.
Furthermore, we determined during which time period in pregnancy estimation of gestational age is most accurate. To derive growth reference curves for fetal biometry, gestational age was established based on CRL or BPD at enrolment using the equations derived in this study. Royston and Altman have shown how to apply a particular type of statistical model to longitudinal data to produce growth centiles and the same model may source be used to calculate valid size centiles 16 This approach is termed multilevel modeling and was used in the Generation R study.
A maximum of three ultrasound visits was used for each pregnancy, one in each of the periods described in the study design, to prevent selection bias. If more than three ultrasound examinations were performed we selected those carried out at the initial scheduled visits. For the BPD curve, measurements that were used for pregnancy dating were excluded. The best fitting fractional polynomial curves were chosen by comparing the deviances and by visually checking the goodness of fit.
The curves were fitted using repeated measurement analysis. Next, regression lines were fitted for the dependency of the residual SD on gestational age Subsequently, plotting the SD scores against gestational age was used to assess correctness of the model. Finally, centiles were derived and the curves were plotted on the data. The curve for FL was established from 12 to 40 weeks to ensure sufficient bone mineralization for reliable measurement. The TCD curve was derived from 16 to 36 weeks of gestation.
Characteristics of pregnant women and their newborns are shown in Table 1. For the ultrasound dating of pregnancy serial CRL and 10 serial BPD measurements were obtained during pregnancy. Tables of medians, 5 th and 95 th centiles and plots of individual measurements with the fitted centiles of gestational age are provided in Tables 3 and 4and Figures 2 and 3.